Tester – Function Operator/Exceptions

The Tester class is another one-use class that fits the pattern of the function operator class.  The main run function was changed to function operator function.  The caller in the command line constructor was modified accordingly with the instance renamed from tester to test as was done with the parser instances.

The Tester class also had an error mechanism where its error message member was set if an error occurred.  Both the constructor and the run function can generate an error.  The has error access function returned if an error occurred, and the error message access function returned the error message.  These functions were modified to throw an exception containing the error message (a standard string).  The function operator function (formerly run) no longer needs to return success status as a boolean.  This simplified the command line constructor since errors from both functions are caught with the same section of code.  The error message member and its access functions were removed.

The redundant void was also removed from tester function definitions that don't have arguments.  This was a practice I used when working with C code where the void in the arguments of a function definition indicates no arguments, as opposed to an empty parentheses, which could also indicate the old Kernighan and Ritchie (K&R) style function definition, which preceded the typed function definitions introduced with the first ANSI C standard.  This void usage is used throughout and will slowly be removed as there is no reason to use it anymore.

[branch misc-cpp-stl commit 738eba02e1]